A window is a transparent opening in a wall or door that allows the passage of light and, if not closed or sealed, air and sound. Windows may be glazed or covered with some other transparent or translucent material. Windows may be held in place by frames, which prevent them from collapsing in. Certain glazed windows may be opened, to allow ventilation, or closed, to exclude inclement weather.
Window frames may include corner keys and lineal profiles. A lineal profile may be a sash profile or a frame profile. Window frames and doorframes typically include a plurality of mainframe profiles. In a typical window frame, the top frame profile is usually identified as the header, the bottom frame profile as the sill, and the remaining two side profiles as the side jambs.
Window frames may include corner keys to connect sash or frame profiles together.